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Java > Open Source Codes > org > apache > commons > jexl > parser > ASTWhileStatement


1 /*
2  * Copyright 2002-2006 The Apache Software Foundation.
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  * http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16
17 package org.apache.commons.jexl.parser;
18
19 import org.apache.commons.jexl.JexlContext;
20 import org.apache.commons.jexl.util.Coercion;
21
22 /**
23  * A while loop. Syntax: while ( expression ) statement
24  *
25  * @author Dion Gillard
26  * @since 1.1
27  */
28 public class ASTWhileStatement extends SimpleNode {
29     /**
30      * Create the node given an id.
31      *
32      * @param id node id.
33      */
34     public ASTWhileStatement(int id) {
35         super(id);
36     }
37
38     /**
39      * Create a node with the given parser and id.
40      *
41      * @param p a parser.
42      * @param id node id.
43      */
44     public ASTWhileStatement(Parser p, int id) {
45         super(p, id);
46     }
47
48     /** {@inheritDoc} */
49     public Object JavaDoc jjtAccept(ParserVisitor visitor, Object JavaDoc data) {
50         return visitor.visit(this, data);
51     }
52
53     /** {@inheritDoc} */
54     public Object JavaDoc value(JexlContext jc) throws Exception JavaDoc {
55         Object JavaDoc result = null;
56         /* first child is the expression */
57         SimpleNode expressionNode = (SimpleNode) jjtGetChild(0);
58         while (Coercion.coerceBoolean(expressionNode.value(jc)).booleanValue()) {
59             // execute statement
60 result = ((SimpleNode) jjtGetChild(1)).value(jc);
61         }
62
63         return result;
64     }
65 }
66
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